With devices or overall systems consisting of several interconnected partial systems the functions of the partial systems may be mutually dependent. If, for example, one partial system fails, it may become necessary to switch off the other partial systems or to restrict their range of functions.
If a partial system generates a voltage, for example, the voltage generation may presuppose the presence of an electrical consumer. The presence of an electrical consumer can be determined by detecting the occupancy state of a plug-in connector, into which the electrical consumer is plugged. If a connector is detected in the plug-in connection, the partial system may generate the voltage. If there is no connector in the plug-in connector, voltage may not be generated. The following partial systems dependent on this partial system are thereby possibly likewise restricted in their permitted range of functions.
Interconnection of the partial systems in the device can take place, for example, in that the voltage supply of the partial system following in each case is made available by the partial system preceding in each case. If an error or a critical functional state is identified in the preceding partial system, the voltage supply of the following partial system and thus of all following partial systems is switched off. This ensures that if an error state occurs the following partial systems are switched off and do not execute functions which may lead, for example, to destruction or damage of partial systems or the overall system.
Interconnection of the partial systems in this case takes place hard-wired via the respective voltage supplies of the partial systems. The number of partial systems must be taken into account in designing the circuit.